There are a variety of types of coin operation based slot or gaming machines in widespread use, including for example rotating reel mechanical slot machines, electronic reel machines and video poker machines.
In a basic mechanical slot machine, the player inserts a coin and pulls down on the slot machine handle or presses a button to initiate the game. For a rotating reel machine, three or more parallel, rotatable reels with an assortment of fruit, number and/or bar symbols are then caused to spin until each reel reaches a resting position. The success or failure of the game is then determined by comparing the combination of reel symbols across an active payline with a table of winning combinations posted on the slot machine. The basic mechanical slot machine windows are frequently made large enough to show three or more adjacent symbols on each reel and thereby allow betting involving multiple rows or paylines.
There have been many improvements to the basic slot machine, including the use of video monitors to display an imitation of the parallel, rotatable reels, rather than having actual reels themselves. In operation, these electronic slot machines simulate the rotation of a physical reel, but typically select the final symbols through use of random numbers generated by a microprocessor rather than any physical rotation of reels. In other words, the final symbols for each simulated reel in the electronic slot machine are randomly selected by the microprocessor and then displayed on the video monitor at the appropriate time and position.
Gaming machines manufactured prior to 1990 generally allowed only for the player to deposit coins or tokens to initiate a new game. Typically such slot machines accept coins or tokens of only one denomination to play a game. The accepted coins are stored in a coin hopper contained in the machine. Because these machines accepted coins of only a single denomination, a player must have that denomination of coin to play the slot machine. Casinos may employ personnel to provide change for bills to players at the slot machines so that the players do not have to leave the machines if they wish to continue playing, but do not have the correct denomination of coin. Winning game plays are determined randomly by the slot machine which pays out to the winner coins from the coin hopper. Coins dispensed from the coin hopper fall into a payout tray, where they can be collected by the player or used to initiate a new game.
Gaming machines may also have a game credit meter visible to the player which is incremented in the amount corresponding to the number of coins inserted by the player or added as specified by the outcome of a winning game. Game credits can be cashed out for the corresponding number of coins, or used to initiate a subsequent game. The play and payout functions are activated by specific operator switches on the face of the gaming machine, accessible to the player, which in turn are connected to a microprocessor based controller within the gaming machine. The microprocessor based controller also controls the operation of the coin hopper in the gaming machine. The coin hopper is thus the coin receiver, coin storage and coin dispenser for the gaming machine.
In approximately 1990, it became increasingly common for the manufacturers of gaming machines to incorporate currency validation devices or bill validators into the gaming machines. The bill validators allow a player to insert paper currency directly into the gaming machine. The bill validator devices are mounted either inside of the gaming machine, or externally in close proximity to the gaming machine. Upon receipt of the paper currency and verification by the bill validator, an output signal from the bill validator instructs the controller of the gaming machine to issue credits based on the denomination of the deposited currency. Credits are thus incremented onto the credit meter without a player having to physically insert coins. The use of bill validators eased new game initiation and enhanced player retention.
However, the gaming machines which have bill validators generally allow for player payout or cashouts only in the form of coins. Due to the convenience afforded the player through the use of the bill validator, fewer coins are utilized to initiate new games and also thereby replenish the coin supply in the coin hopper. Thus, a constantly depleting supply of coins within the coin hopper available for payouts has been the typical result. By comparison to older machines which did not allow for acceptance of paper currency, the operators of gaming machine which have bill validators have had to manually fill the coin hopper with coins much more frequently when player payouts have emptied the coin supply in the gaming machines.
Casinos have thus had to increase the number of change persons who circulate in the gaming machine area to exchange coins or tokens for currency bills and replenish the coin hoppers. The change persons must oversee and distribute a large number of coins of varying denominations. Very often a casino will have gaming machines that accept, for example, nickels, quarters, fifty cent pieces or dollar coins as well as dollar, five dollar, twenty five dollar or one hundred dollar tokens. In addition to the inherent problems of carrying about a large amount of change on the casino floor, this method of supplying both machines and players with change complicates the accounting procedures, increases security concerns and requires more personnel.